Best Distribution?

I'm definitely planning on installing the Zimbra Network Edition trial, and have a decent x86_64 machine to test it on. Right now, my entire infrastructure is based on Debian, and I'd like to stick to it or Ubuntu if I can.

However, it only seems that there's x86_64 packages for RHEL 4. Does anyone have some experience building from source? Is it worth it for a production environment?

Also, would using a Server Appliance (VMware or otherwise) be absolutely crazy for a production environment?

xen - it'll rock your world

I like and recommend RHEL for the NE edition; but you do realize that you don't need to run a 64bit os just because you have a 64bit capable machine...
Some people do go the server appliance vmware route.

Now hold on to your socks. This will make you gasp-but it's a kick A method-and it just gets better and better for larger installs.
Personally, I like the concept of virtual machines-this method is a little different than the server appliance route:

-Xen running on Fedora Core (or RHEL 5 also has it now)

-Running virtual instances of RHEL 4 (either 32bit or 64bit)

Say you need more resources or performance for a particular customer/domain/usergroup-just transfer it to a machine that’s got more under the hood.
You can move the virtual instances around from physical machine to another physical machine/blade/whatever-LIVE.
It even switches over the network connections last, with milliseconds of downtime-ie: the user doesn't notice.

Need a backup? -snapshot
Need to make a quick duplicate to get another server up and running? -piece of cake. If you take a snapshot early of a clean build (or even your latest good build) change the ip addresses, servernames, point them at a storage location, etc - and viola!
Need another MTA? -load a virtual instance of just that
And the icing for service providers: Do mailstore virtual instance(s) per domain. You can instantly find exactly what machine(s) are dealing with which customers-put the domains in the naming scheme-and just check where the instances are! Also, while you still need to delete the users via the admin console, you can then just turn off that entire virtual instance if you no longer host that customer.

jholder - Granted, a virtualized 32-bit instance wont really benefit from 64-bit addressing, but in reality I don't think I'd personally need it for what I'm doing now, as this box only has 2 Gb of RAM anyway. However, does the actual JVM balloon up to 4 Gb or more?

mmorse - For what I'm doing, I don't really need multiuser capabilities. This is really just for a domain with about 100 users all on the same domain, so it doesn't make a whole lot of sense to do that. However, last I checked (granted, a couple months ago), Xen live migration doesn't always keep sockets perfectly. I remember seeing the occasional TCP retransmission. No big deal honestly, but it's not *perfect* either.

jholder - Granted, a virtualized 32-bit instance wont really benefit from 64-bit addressing, but in reality I don't think I'd personally need it for what I'm doing now, as this box only has 2 Gb of RAM anyway. However, does the actual JVM balloon up to 4 Gb or more?

mmorse - For what I'm doing, I don't really need multiuser capabilities. This is really just for a domain with about 100 users all on the same domain, so it doesn't make a whole lot of sense to do that. However, last I checked (granted, a couple months ago), Xen live migration doesn't always keep sockets perfectly. I remember seeing the occasional TCP retransmission. No big deal honestly, but it's not *perfect* either.

I have been running Xen virtual since M2, and it's absolutely wonderful if you can afford the 10-20% performance hit. On the other hand you can strip the environment, and isolate mail from other services like web and other applications. Good for security and management. Virtualization (in my opinion) is a pretty good solution. 64 bit is also a bit overrated in my experience. You have to be doing large mail volume for a fairly large set of users to make it worth it.

sry jlassoff, I know this is going beyond the size/scope of what your doing...oh btw wiht 100 users-suggested that around there you start to move away from Raid 5 (As the files are so small-the time raid 5 takes to write hundreds of little files is pretty long.) Really kinda also dependent on how active your users are, I think the official zimbra stance is if you will at some point have 50 connected users-try to avoid raid 5. That being said-if you already plan to use it-that's cool-but you'll know later what 'upgrade' will be your biggest performance gain.

on the VS/VM topic again:
And ya-try to do your transfers at say 2/3am when fewer people are connected...
but another thing that rocks about virtualization:
big providers: say you find that one of your data center's is getting more traffic for a customer-transfer your vm's (and connected data-though that's always easier) to the more used datacenter etc.